added locale sk-SK. thx Slavko slavino.sk
add git rev to build dirname
keep long living references to timers
add '-debug' to build dirname when applicable
* more accurate startup event detection
* when start_hidden, hide window on first x11.MapNotify instead of hiding all
  windows short after the "startup event".

  This prevents having visibility falsely corrected for windows that are
  displayed after the "startup event", and thus having to click twice on the
  tray icon to actually restore windows.
* display popup menu window items for all application, not only browsers
* cleaning